Scientific American 2011-05-25 – Plans call for running the 3,200-kilometer-long pipeline from Canadian tar-sands fields to U.S. Gulf Coast refineries
Tar sands oil (or “tar sands”) is slang for bituminous sand, a mixture of sand, clay, water and an extremely gooey form of petroleum known as bitumen, which resembles tar in appearance. Extracting commercially viable crude oil from tar sands is especially difficult because the thick and sticky mixture won’t flow unless it is heated or diluted with other hydrocarbons. Turning the extracted bitumen into liquid fuel requires large inputs of energy; the process also uses, pollutes and wastes large amounts of fresh water.
Research has shown that these processes alone generate as much as four times the amount of greenhouse gases per barrel of final product as the post-extraction production of conventional oil. Taking the entire life cycle of both final products into account, the extracting, processing and burning of liquid fuel from tar sands emits between 10 and 45 percent more greenhouse gases overall than conventional crude. Extraction of oil from tar sands also damages land to the point where it can no longer sustain forestry or farming. …
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